The unbendable arm isn't a trick as long as you take steps to make sure people don't turn the arm for advantage. We have gone over this before in class as part of a discussion of Sanchin. The arm isn't really unbendable as I'm sure most here know but when you have the right focus and concentration you can very significantly increase the amount of force it take by somebody to bend your arm.

This was used to help explain how our balance and focus should be for the part of Sanchin where you do the slow palm push outs. (atleast we do it that way) Your suppose to be focused and be able to root into the stance and be able to push somebody back from you. Very very hard to do without intense concentration if they resist even a little. If you focus properly you can push pretty darn hard.

Can I suggest that the purpose of the unbendable arm is to use the structure to convey the forces on the elbow crease to the ground. IOW, the tester should feel like they're pushing against the ground - not the elbow crease.

It's not a trick, insofar as a demonstration of the body skill required in grounding certain forces at supposedly "weak" points in the anatomy.

I've read one particulr explanation of this trick as a demonstration of the antagonistic action of the triceps and biceps, but to me, it merely shows the lack of real understanding as to the purpose of this EXERCISE.

As far as I'm concerned, canting your arm so that the elbow crease is facing inward is NOT advisable, I've seen people almost pop the joint capsule as a result... not a nice way to have your arm broken....

<<The unbendable arm isn't a trick as long as you take steps to make sure people don't turn the arm for advantage.

Apologies for not responding sooner, trying to "catch up" in many arenas. Please explain the not turning the arm a bit more want to make certain I comprehend precisely what you mean... think I know where you are going, just want to make sure!

<<when you have the right focus and concentration

The "crucial" words, how does that work ?

<<the part of Sanchin where you do the slow palm push outs. (at least we do it that way) Your suppose to be focused and be able to root into the stance and able to push somebody back from you.

Your Sanchin stance unless far, far wider than most (ie equavilent to the horse stance, forward leaning stance, etc.) or unless angled very very differently won't support the direction of the intended pushing action. Does not the action require the structure be aligned correctly for the particular action, in this case a push?

Most of these stunts are just that and have nothing to do with martial arts skill.

Take the "bed of nails" first. It takes some knowledge to know how many nails to put in the bed and how far apart to space them out - and perhaps even the type of nails to use. Each bed has to be custom made according to the weight of the person.Think of a karate punch for a moment. You hit with the 2 knuckles to focus the force into a smaller area. The bed of nails works the opposite way. You spread the body weight over enough nails so there is little to no weight on any one nail. Spread the nails out too far and don't distribute the weight properly and all the martial arts skills in the world won't stop them from poking holes in you.

The same thing pretty much gors for breaking concrete on the body. Put the wrong size of concrete on the wrong part of the body - or strike the wrong part of the concrete with the sledge hammer - and you're looking at an injury.

Hot coal walking is mainly a matter of not setting your feet flat down on the coals long enough to burn. You have to keep moving. You'll also see that these guys don't really walk on red hot coals, they let them cool somewhat and get to a better temperature. If you stop, you burn your feet. Once you get the coals to a safe temperature, it's much more of a mental game than physical. If you focus on the heat and get nervous about getting burned, you'll get burned. If you focus on the goal of walking non-stop to the end of the coals and don't think about the heat, you'll be ok. Just like breaking boards with a punch. Every person over 80 pounds can generate enough force to punch through a pine board. But you have to focus through it. Without training, most people will not be able to do that. They will focus on the front of the board and hurt thier hand. In the same way most people will focus on the heat and get burned.

I can't explain the weapon against the throat trick. I knew a karate teacher who used to do this with arrows. He would take a stance and someone would press the arrow into his throat until it (the arrow) snapped in half. Of course he would never do this with just anyone. His assistant was trained in the stunt as well.

Unbendable, which we learn as part of Aikido, is not a stunt in the same classification. It requires proper body positioning which can take some practice. But it does have real martial applications, in applying arm bars or doing things like our "hitting elbow throw".